Bring a large pot of water to a boil and generously salt. cook fettuccine according to package directions until al denté. Take care not to cook the pasta any longer, as it will continue to cook more once you add it to the sauce.

Meanwhile, pour the cream into a large skillet with the butter and lemon juice. Turn the heat to medium-high and cook until the butter melts and bubbles form. Stir to combine, add the minced rosemary, and reduce heat to a simmer.

When the noodles are done cooking, drain them in a colander but do not rinse. Remove the cream sauce from the heat and add the noodles to the pan, tossing to coat the noodley strands thoroughly. Add the parmesan cheese, lemon zest, kosher salt, and pepper to the cream and toss again. Place back on the burner over low heat and toss until the sauce thickens, about 1-2 minutes. Serve with more Parmesan cheese and more fresh zest of lemon.